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Aux heat only on heat pump

Hello all.
I'm not looking for a diy answer, just trying to understand my heat pumps operation because I will have a HVAC professional do any work needed. I have a Trane xe 1100 condenser and an american standard air handler with electric heat strips (TWH024B140A1). This unit is a 1993 model. (it's old, I know.) When the system is calling for cool, all systems work properly; i.e. condenser (fan and compressor) are running and the air handler runs. However, when the tstat calls for heat, only the air handler and electric heat strips come on. The condenser does not operate at all. I have looked up the thermostat the previous owner installed and the manual says it is not to be used with Heat Pumps that have back up heat (RTH221b1021). With this knowledge, I have a few questions.
1. Since the tstat appears to be wrong for the system, would it only be sending the single to the air handler to run during heat and not sending the signal to the condenser?
2. Could there possible be another part in the condenser that has locked out the heat operation? Everything runs in cool.

If you aren't using a HP stat, that's the problem. It does not ask for the outdoor unit to come on for heat, only the backup. Have a tech put on the right stat and check the system over. It is rather long in the tooth for a heat pump but it is a Trane.

If you aren't using a HP stat, that's the problem. It does not ask for the outdoor unit to come on for heat, only the backup. Have a tech put on the right stat and check the system over. It is rather long in the tooth for a heat pump but it is a Trane.

Thanks BladLoonie. I'm going to make the call to have the tstat changed out by a HVAC pro. I have a Honeywell Pro 3000 left over from an previous job but I'm unsure of the wiring at the tstat since the previous owner has installed the wrong tstat currently and I have no manuals or wiring diagrams for the system. I've done my best to trace the wiring down and it appears the wiring to the AHU and out to the condenser are correct. Here's hoping that a new tstat solves my issue. All other components seem to be in working order. Fingers crossed.

Get a good stat, some utility providers offer rebates. Stay away from Nest, my choice is honeywell, all i have ever had for my own use.

Thanks, will do. I will have the HVAC tech out, hopefully, soon to replace it. A friend gave me a Nest to put in another house but I'm not brave enough to have it installed because everything works just fine there.

Just remember, simple is better with a heat pump. The “energy saver” type thermostats that set the temperature back when your not home can actually increase your electric bill by using the electric heat more often.
The system will be happiest when left to a constant setpoint.
Because every time the electric heat strip comes on your electric bill goes up.

Just remember, simple is better with a heat pump. The “energy saver” type thermostats that set the temperature back when your not home can actually increase your electric bill by using the electric heat more often.
The system will be happiest when left to a constant setpoint.
Because every time the electric heat strip comes on your electric bill goes up.

I read that recently on this forum and had never considered that before. Very sound advice. Thanks

Just remember, simple is better with a heat pump. The “energy saver” type thermostats that set the temperature back when your not home can actually increase your electric bill by using the electric heat more often.
The system will be happiest when left to a constant setpoint.
Because every time the electric heat strip comes on your electric bill goes up.

I read that recently on this forum and had never considered that before. Very sound advice. Thanks